LONGLINE FISHING FOR DEEP-SWIMMING TUNAS 

 IN THE CENTRAL PACIFIC, 1953 



By 



Richard S. Shomura and Garth I. Murphy 

 Fishery Research Biologists 

 Pacific Oceanic Fishery Investigations 

 U. S. Fish and Wildlife Service 



This is the fourth— in a series of reports on a survey of the 

 deep-swimming tunas of the central equatorial Pacific. This survey 

 has been conducted by the Pacific Oceanic Fishery Investigations 

 (POFI) as a portion of a larger investigation embracing the hydro- 

 graphy and productivity of the central Pacific as well as the fishery 

 resources (Sette MS). 



Herein we summarize the salient features of six equatorial 

 fishing cruises made between 140 W. and 170 W. longitude in 1953 

 (table 1, fig. 1). In addition, the results of a considerable amount of 

 Japanese fishing in 1953 between 160 W. longitude and 180 are dis- 

 cussed. Complete summaries of the POFI cruises and of the catch 

 data from the Japanese fishing are given in the appendix. 



We use the vernacular names of the fishes throughout this 

 report. These, with their commonly accepted scientific names, are 

 listed below: 



White-tipped shark, Carcharinus longimanus (Poey) 

 Silky shark, Carcharinus sp.^/ 

 Great blue shark, Prionace glauca (Linnaeus) 

 Bonito shark, Isurus glaucus (Miiller and Henle) 

 Marlin, Makaira sp. 



Sailfish, Istiophorus orientalis (Schlegel) 



Wahoo, Acanthocybium solandri (Cuvier and Valenciennes) 

 Dolphin, Coryphaena hippurus (Linnaeus) 

 Yellowfin tuna, Neothunnus macropterus (Temminck and 

 Schlegel) 



— Fishing from July 1950 to December 1952 is summarized 

 in Murphy and Shomura 1953a, b, and 1955. 



2.1 



— A species closely resembling C. floridanus Bigelow, 



Schroeder, and Springer, and C. ahenea (Stead). 



